Method of grinding valve seats and similar areas



Nov. 21, 1944. R.- s. BEVERLIN METHOD OF GRINDING VALVE SEATS ANDSIMILAR AREAS Filed April 17, 1944 IIIII I 1 rill/1 i v Furthermore, in

1 Patented Nov. I

. 'I ivrn'rnooomonmnme VALVEQSEATSIAND, a 1 sIMILAR R As corporation.ofaOhio .Appii 'iaitnat f 7 wersefiam- 531,391

flsolaims. (c1. 51+241- v are eylinderfwith a part in iullandwitha valveseat grinding tool in operative position "therein,

i jl'l'his invention relates "primarily to the artjfof indihg valveseats, offinterna'l cornbustion'engines; particularly those of the. typehaving closed Qcylinderheads withthe .valve seats in such heads,

jasiri radialai'rc'raft engines," thus requiring access thereto.forij'giindin purposes to be had through the open'inner end of thecylinder.

' ,In'thegrindi "g of valve seats in such a cylin- ,dei the: grindingtool .is} disposed within the -"closed"cylinder head end thereof whereiteis. difficult ofaccess for the purpos'e'of applying thereto thenecessary; grinding pressure, and theoylinder together with meansattachedthereto fon'pracbore is usua'lly of suchjsmall diameter that theis vless than that normally required, the efficiency of a the grinding:operation is gradually. reduced,

'both in time and results, and this isincreased if the plane of the'valve' seatis inclined to the cylinder axis, 1 t I v the grindingsofsuch Ivalve seats, 'a' liquid coolant is introduced interiorly of tj'tool ,must'besmall sothatitsWei'ght is notsuifl- ;cient to ,impart'.the desired grinding pressurej "agains t .thevalveseat. 'If'the grindingpressurethecylinder' and flows down to and in engage- I ment Withtheedge of the grindingwheel. The

"hi h 'spe'ed'ofthe wheel causes this-coolant to flow to and bethrownfrom the peripheral edge ;of the wheel by lcentrifugalqaction sothat very "little if any of the coolant will reach the grinding surface,thereby resulting 'in a hot grinding operation. An object oftheinvention is the provision of a simple, eflicient and 'novelfrnetho'dandmeans for acting on the grindingwheel of a valve seat grinding .toolthrough the valve seat passage to apply a predetermined grindingpressure thereto Another'object of the" invention isf to'utilizepneumatic suction through the valveseat passage ofaninternal combustionengine cylinder to act on a grinding tool for thefvalve seat. of suchpassage to hold it to the seat'withafpredeterrnined pressure to effectthe desired grinding operation. Another object of the invention is theprovision of'aisirnple' jand efiicient method, ofpneumatic -character,operable throughthe valveseatopening of a cylinder of theclas'sdescribedto not (only act to h a inding wheel in seat grinding "ticingthe feature of the'invention."

Referring to the drawing, 1 designates a cylinder'of afradialtypeaircraft engine, with the head or closed end thereof I provided-withtwo passages 2 one of which forms the inlet passage andthe other theexhaust passage forthe cylinder vand each havingat its inner end thecustomary-valve seat 3. In eachpassage 2,-in-axia1ly aligned relation tothe valve seat opening his a valve stem guide "opening 3 4 adaptedtoreceive and guide the 'movements "of the associated valve stern (notshown); when the 'valve'is" removed *from the cylinder head, the guideopening :4

receives and centers a pilot stem 5, onefend'ot which -pro5ects throughthe -valve 'seat'iopening and into-the cylinder '-to'-form a mount andguide for a valve'seat grinding tool 6, as well understood in the art.Thetool 6 is preferably-but not construction -due to *itsuse incylinders having small diameter bores. Nothing novel is claimed forthe-tool itself and -ittherefore need not be I --more specificall'describedp :A' liquid coolant; 'in thepresent instance, is

suppliedto the surface-being ground from a hose "or tube-8 whichreceives its supply of coolant from any suitable source and-has itsdischarge end terminating within the cylinder adjacent to one sideso'thatthe coolant will flow down-the inner side wall of the cylinder tothe valve seat a3 being'ground; I

position under a'predetermined pressure, but also to prevent a coolantsupplied to thewheel' from being drawn away fromits seat grindingsurface by centrifugal action. v I

Other objects and advantages of the invention will be apparent from thefollowing description and from the accompanying drawing. i 1

The drawing is a central longitudinal section During the grinding-of avalveseat thesmallnessand c onsequent lightness of the tool 6 prevents=it-from exerting by g-ravity action-the necessary pressure of itsgrinding wheel; -|flagains't the-' valveseat 3 to eifect a -rapid and-efficient grinding operation, and due to'the small diameter of thecylinder bore it"is, difiicult to apply any manual pressureto the toolfor the purpose. In

" order to compensate for this lack of grinding pressure, the outer endof the passage'2 leading to or from the valve seat opening, as'the casemay be, is connected up to a .vacuumfsource whereby a suction action isapplied through such passage and acts against the grinding wheel I tohold it to the valve seat under a predetermined pressure, which isdetermined by the suction pressure. This method of applying grindingpressure to the grinding wheel is not only eflicient in obtaining thedesired grinding action of the wheel on the valve seat, but also indrawing the coolant to the valve seat and coacting grinding surface ofthe wheel to have the desired cooling action thereon rather than beingcarried to the extreme peripheral surface of the wheel away.from thevalve seat and thrown therefrom by centrifugal action. This initself isan important feature.

In the illustrated embodiment of the invention, l designates a tank fora liquid coolant and into which the open end of a suction pipe issubmerged. This pipe connects with a suitable suction source indicateddiagrammatically at l2, and between this source and'the tank [0 the pipehas a side connection at I3 with the outer end of the passage 2, thevalve seat of which is to be ground, The connection I3 is adapted toseat against the outer marginal edge wall of the passage 2 and to besecured thereto by screws, or in any other suitable manner. a The vacuumpressure may be determined by the height of the coolant column in thelower end of the pipe I and in practice it is found that from sixteen totwenty inches raise of liquid in the pipe is sufiicient. The top of suchcolumn, however, should be below the connection l3, so that the coolantwhich enters the passage 2 may flow outward therefrom through theconnection I3 and pipe, I I to the tank [0. In the present instance, thecoolant supply tube 8 leads from the tank I0 and has a pump l5interposed therein. 7

While, in the use of an eccentric type of grinding tool, as illustrated,a clearance space is present between the seat and grinding wheel due tothe eccentric seatingaction, this clearance is customarily abouttwenty-one thousandths of an inch at its widest point and therefore isnot sufficient to seriously interfere with the desired suction action onthe wheel. The presence of such clearance also facilitates the drainagemovement of the coolant over and through the seat by the suction action.i v

While the invention has been particularly described for' use inconnection with the grinding of valve seats disposed interiorly ofengine cylinders, it is not desired to restrict it to such use, as itmay be used to advantage in the grinding of any area which is circularor substantially circular and has a passage leading inwardly therefrom,whereby suction within the passage at the inner side of the grindingtool will permit atmospheric pressure, acting on the tool at its outerside, to hold it to the seat or area being ground.

I wish it understood that my invention is not limited to any specificconstruction, arrangement or form of the parts, as it is capable ofnumerous modifications and changes without departing from the spirit ofthe claims.

Having thus described'my invention, What I claim as new and desire tosecure by United States Letters Patent, is:

1..The method of holding a valve seat facing passage.

tool in operative coaction with a valve seat at the cylinder end of apassage having communication with a cylinder, which consists in creatinga vacuum within the passage whereby atmospheri pressure at the cylinderSide of the tool acts on the tool to hold it under predeterminedpressure in facing coaction with the valve seat.

2. The method of holding the grinding wheel of a valve seat facing toolin predetermined grinding coaction with a valve seat at the cylinder endof a passage which is in communication with the cylinderof an internalcombustion engine and wherein the wheel closes or' substantially closesthe passage, which consists in ap-' plying a predetermined pneumaticforce on the wheel through said passage to hold it in predeterminedgrinding coaction with said seat.

3. In the art of grinding the valve seats of the cylinders of internalcombustion engines wherein the rotatable grinding Wheel of a valve seatfacing tool has grinding engagement with a valve seat internally of thecylinder and wherein a liquid coolant is supplied to the wheel, themethod of preventing such liquid from being thrown away from the seatgrinding portion of the wheel by centrifugal action, which consists incausing a pneumatic force to act through the cylinder and around thegrinding wheel to counteract the said centrifugal force and cause thecoolant to partially at least flow outwardly from the cylinder over thevalve seat.

4. In the art of grinding the valve seats of cylinders of internalcombustion engines wherein the rotatable grinding wheel of a valve seatfacing tool has grindingengagement with a valve seat internally of thecylinder and wherein a coolant is supplied to the wheel and seat, themethod of holding the wheel to the seat. with predetermined grindingforce and also preventing the coolant from being thrown from the seat bycentrifugal action due to the rotation of the wheel during grinding,which consists in applying a predetermined suction on the wheel awayfrom the cylinder and through the passage leading from within the valveseat.

5. The method of holding a grinding tool to an area to be ground andwherein aspace is provided within such area and is open thereto, whichconsists in creating a vacuum Within said space-whereby atmosphericpressure at the outer side of the tool with respect to said space actson the tool to hold it; under predetermined pressure in facing coactionwith said area.

6. The art of grinding substantially circular areas bounding an openpassage leading inwardly through said area wherein a rotatable grindingtool has grinding coaction with the area in substantially closingrelation to said passage and wherein a coolant is supplied to the wheeland area, the method of holding the wheel to said area withpredetermined grinding force and also preventing the coolant from beingthrown from the area by centrifugal action due to the rotation of thewheel during grinding, which consists in applying a predeterminedsuction in said passage" and to the side of the wheel exposed tothe,RQBERT s. ,BEVERLIN;

